Geothermal is the Cadillac of heating. Steady, quiet, efficient on the coldest night of the year. It is also the one system where a sizing mistake gets buried in the yard and stays there.
Here is how a ground source system is sized, what the loop has to handle, what the permit side looks like, and when it actually pays for itself in Ontario.
It starts like any other system: a room-by-room CSA F280 heat loss at your design temperature. That sets the size of the heat pump.
Then the loop. The loop has to pull enough heat out of the ground, all winter, without the ground around it getting too cold. That depends on the heat loss, how many hours the system runs, and your soil, rock and groundwater.
Ground source systems in Canada are designed and installed to CSA C448. Ask anyone quoting you whether their design follows it.
A loop sized too small. The system works fine the first winter, then loop temperatures sink year after year and efficiency drops. Digging it up is not a weekend job.
Pipe buried in trenches. Cheaper to install, needs a lot of land. Common on rural lots.
Pipe in drilled holes. Fits small lots, costs more to drill. Rock and depth matter.
Uses well water directly and returns it. Needs plenty of good water and has its own rules. Not for every lot.
Possible on some waterfront properties. Has its own approvals and practical issues.
Digging the loop while the site is already torn up saves a lot of money.
Against oil, propane or electric heat, the savings come faster.
Big houses in cold areas run the system enough to pay it back.
Low water temperatures suit a ground source heat pump perfectly.
Against a cold-climate air-source heat pump, the gap is smaller than it used to be. Run both through the numbers. See cold-climate heat pumps.
Expect a building permit for a geothermal heating system. Some municipalities list it specifically. Drilling has its own rules, so use an experienced, accredited driller who knows them.
Rebates: Ontario’s Home Renovation Savings program pays for ground source heat pumps, with the largest amounts for homes not heated by gas. Pre-approval is required before installation. See the rebate guide.
Thinking geothermal? Get the heat loss first. It is the number the whole system, loop included, is designed from.
Get Free Quote →Yes. The heat pump is sized from the heat loss like any system, but the ground loop is sized from the heat loss plus the soil or rock conditions. Ground source systems in Canada are designed and installed to CSA C448. An undersized loop is the classic failure, and you cannot easily fix a loop once it is buried.
Expect so. A ground source heat pump is a heating system, and some municipalities list geothermal specifically as a permit item. Drilling also has its own rules. Ask your building department, and use an experienced, properly accredited driller.
It is more efficient, especially on the coldest days, because the ground stays warmer than January air. It also costs a lot more to install. It makes most sense on new builds with space for a loop, high heating loads, or no gas. The heat loss tells you whether the numbers work.
Ontario’s Home Renovation Savings program pays rebates for ground source heat pumps, with the biggest amounts for homes heated by electricity, oil, propane or wood. See the rebate guide for current amounts and rules.
Horizontal loops are cheaper but need a lot of land. Vertical loops use drilled holes and fit small lots, but drilling costs more. Rock, soil and water on your lot decide a lot of it.
Yes, and it is a good match. Radiant floors want low water temperatures, which is exactly what a ground source heat pump does efficiently. See radiant floor design.
Send your drawings. We calculate the heat loss room by room at your design temperature, plus the distribution design for ducts or radiant floors.